What is the correct protocol for collecting and transporting a Clostridium difficile stool specimen?

• A. Use a white top container, fill to the line with liquid stool, close and shake to ensure fixative is well mixed, and transport to the laboratory at room temperature or keep refrigerated at 4°C for delivery within 24 hours.
• B. Use a red top container and ship unstabilized stool at ambient temperature.
• C. Collect a solid stool in a blue top container and store at -20°C.
• D. Only collect for 48 hours; send immediately without fixative.

Answer: (A)

Preserving the stool sample for Clostridium difficile testing requires a transport system that includes a fixative to stabilize the organism and any toxins during transit. The white-top container provides that fixative, and filling to the specified line ensures the correct fixative-to-sample ratio so the preservation is consistent. Shaking mixes the fixative thoroughly with the liquid stool, ensuring uniform preservation. Transport at room temperature or refrigerated for up to 24 hours keeps the sample from degrading before it reaches the lab, which helps maintain the accuracy of the test. Using an unstabilized container won’t protect the sample, and freezing or using other container types can alter components of interest or compromise results. Having a fixed window and proper preservative is essential for reliable C. difficile testing.